systemd-stdio-bridge - D-Bus proxy
systemd-stdio-bridge implements a proxy for a D-Bus endpoint. It expects to receive an open connection to a bus when started, and will also connect to a (different) bus as a client. It will then act as a server on the first connection, and forward messages between the two busses. This program is suitable for socket activation: the first connection may be a pipe or a socket and must be passed as either standard input, or as an open file descriptor according to the protocol described in sd_listen_fds(3). The second connection will be made by default to the local system bus, but this can be influenced by the --user, --system, --machine=, and --bus-path= options described below.
The following options are understood:
-p PATH, --bus-path=PATH
On success, 0 is returned, a non-zero failure code otherwise.